Electric heater.



No. 643,744. Patented Feb. 20, I900. G. C. HAWKINS.

ELECTRIC HEATER.

(Application filed Mar. 13, 1899.)

(No Model.;

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GARDNER O. HAWKINS, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO GEORGE E.SMITH, OF SAME PLACE.

ELECTRIC HEATER.

SPECIFICATION forming part of Letters Patent No. 643,744, dated February20, 1900.

, Application filed March 18, 1899. Serial No- 708,794. (No model.)

To all whom, it may concern.-

Be it known that I, GARDNER O. HAWKINS, of Boston, county of Suffolk,State of Massachusetts, have invented an Improvement in ElectricHeaters, of which the following description, in connection with theaccompanying drawings, is a specification, like letters on the drawingsrepresenting like parts.

This invention has for its object the production of a novel electricheater adapted for use in cars, steamships, dwellings, factories, &c.,the same being so constructed that it may be easily mounted in workingposition and when started may be made to heat the air in the room orapartment where the heater is located.

Myimproved heater consists, essentially, of

1 a surrounding case, preferably of sheet metal,

suitable resistance medium or coils sustained within the delivery end ofsaid case and 0ceupying a position at or near the delivery end of saidshell, said resistance medium or coils occupying a position between theinner wall of the case and the center of rotation of the motor-shaft,and an electric motor carrying a fan adapted to suck air into said shellat or near the base thereof and force it over the re sistance medium orcoils, said air being heated on its way through said shell and out fromits open or delivery end. Each resistance medium or coil presents asurface of considerable diameter, and they are preferably arranged in acircle, and the fan cooperating with the resistance medium or coils isso constructed and actuated by the electric motor that said fan blowsthe air diagonally out-.

ward across the heated resistance medium or coils, and also, due to thecircular current established in the air within the case by the fan, itresults that the air is made to impinge against a very large portion ofthe cylindrical exterior surface of the resistance medium or coils, andthe greater the surface of the resistance medium or coils directlyimpinged or struck by the blast of air the greater the quantity of heattaken up by the air therefrom. The fan is carried by the shaft of anelectric motor located centrally within the case, the motor beingpreferably inclosed in a shell, the fan standing and turning,preferably, in the case between its ends, one end of the case being openfor the discharge of air, whereas the case at or near its opposite endhas suitable air-inlets.

Figure 1, in vertical section, shows an electric heater embodyingmyinvention. Fig. 2 is a view of the same looking into its delivery end,the resistance-coil H being mostly broken out. Fig. 3 shows part of oneof the resistance-coils detached and enlarged.

The electric-motor shaft a carries a suitable armature which revolveswithin the usual field, and this shaft and field, which may be of anyusual or suitable construction, are sustained in a suitable shellb b.The said shell, as herein shown, is composed of two semispherical parts,each having a flange, as b and b the flange 72 resting on a series ofposts b extended from a base b Thefiange 1) receives upon it the flangeb and suitable screws b extended through said flanges, serve to confinethe semispherical parts of the shell in position on said base.

The electric motor is not of my invention, and I may employ any of theusual forms of electric motor. The fan carried by the shaft a may,however, for the best results have a construction which I will nowproceed to describe. This fan is composed of a suitable bottom plate a,the hub of which may be secured to the shaft a by a suitable set-screw cand two inclined circular walls 0 0 connected by blades 0 so that saidwalls and blades constituting the fan are made to travel in unison withsaid bottom plate. These walls occupy a position each with relation tothe other substantially concentric, (see Fig. 1,) and, as herein shown,the said walls are inclined outwardly away from the center of motion ofthe shaft a. The blades a represented as six in number, are suitablyriveted at their ends, respectively, to the walls 0 0 The fan so madepresents two circular walls open at bottom and top and connected acrossby the blades. The motor and fan are surrounded by and rotate in a cased, having bolted to it at one end a flanged ring cl. open at its outeror delivery end and has at or near its opposite end, preferably belowthe plane in which the fan rotates, a series of inlet-passages d for theentrance of air which is sucked into the case to be heated, said air Thecase isbeing driven through the case into the room or apartment and overthe resistance medium or coils to be described.

The resistance medium or coils 6 shown are substantially cylindrical incross-section, and theypresent a heated surface of considerable diameterin cross-section.

The resistance-coils e are represented as six in number, and they arecomposed of a series of porcelain or other insulating tubes 6, (see Fig.3,) Wound externally with fine Wire 0 said tubes being supported onsuitable studs or carriers e herein represented as sustained by themetallic case CZ within its open end, said tubes being retained on saidstuds by suitable cotter-pins e or otherwise. These resistance-coils areconnected together in series, as best represented in Fig. 2, by a seriesof wires connecting the tubes, and the currentcomes into theresistance-coil through a feed-wiref.

By increasing the area of the heated surfaces of the resistance-coilsthe heat may be greatly augmented, and to provide for this I haveprovided a resistance-coil H, it being composed of a flat ring h, ofporcelain or other insulating material, wound with fine wire h, saidwire being suitably connected in circuit with any usual source ofelectric supply. The resistancecoil II may be supported on arms 7L3,sustained by the shell d at suitable points, said coil being representedas set at an inclination, so that the blast of air heated by the fanafter crossing the coils 6 may impinge directly against the inclinedsurface of the coil II and be thrown back again across the coils e, &c.These resistance-coils may be of greater or less diameter and strength,and they are preferably so located as to stand between the center ofrotation of the face and the inner wall of the case and in the path ofthe air-current generated by the fan.

It will be understood that the air is heated by being impinged againstthe heated surfaces of the resistance-coils, and realizing this I haveconstructed the resistance-coils so that they present a cylindrical massof Wound wire of considerable diameter, thus making them moreserviceable for heating than would be a series of strands of wirestretched across within a tube or frame. The fan shown, it being locatedwithin the case and rotating in a plane between the air-inlets of thecase and the open end or outlet thereof, creates an air-current which isdefined by a combined outward and circular movement, such a current ofair established within the case impinging against a substantially largearea of the heated resistance located within said case.

In my judgment,derived from experiments,

I find that the mere circulation of air about a resistance-coil withoutdirect impingement by a fan or blower does not enable the air to takeany great amount of heat from said coil. This invention is not limitedto the exact number of blades in the fan nor to the exact number ofresistance-coils employed,and

I may employ any desired number of blades or coils, nor is the inventionlimited to the exact manner shown for supporting the saidresistance-coils, but it is preferred to support them by or throughstuds carried by the case, and it is also preferred that the free endsof the coils 6 point toward the center of rotation of the fan.

It will be noticed that the shaft a outside of the shell I) b carriesonly the fan and is not burdened by any wire constituting part of aresistance medium to supply heat.

I provide the interior of the case 61 at a point just below the lowerend of the fan with a stop-plate m, which acts to prevent the air fromcoming into the case from its open end, said plate aiding in inducingthe flow or current of air from the inlets (1 into the inlet of the fanand therefrom through the outlet end of the shell.

Preferably the exterior diameter of the fan is but little smaller thanthe interior diameter of the case, so that the space between therotating fan and the interior of the case is substantially closed, thuspreventing air from coming into the case, due to back draft of the fan.

Vhile I prefer metal for the case, yet this invention is not limited tothe use of metal, as I may employ any other suitable material.

By the term resistance medium used in the claims I intend to cover anyform of resistance-coil having a surface composed of wire wound about itas contradistinguished from wires crossing each other singly, like aseive or network.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is

1. In an electric heater, a surroundingcase, a series of resistancemediums composed of Wire wound about an insulating-core and locatedwithin said case and occupying aposition at or near the delivery endthereof, said resistance mediums surrounding the center of rotation ofthe motor-shaft, an electric motor carrying a fan adapted to draw airinto said case at or near its base, and force said air as ablast overthe resistance medium, said air being heated on its way through saidcase to its delivery end, the construction and arrangement of partsbeing such as to establish air-currents which are defined by a combinedwhirling and outward movement,whereby the airis subjected to therepeated heating action of the heating mediums, substantially asdescribed.

2. In an electric heater, a surrounding case, a series of resistancemediums composed of Wire wound about an insulating-core to present asurface of considerable diameter, said mediums being exposed in saidcase, a fan composed of a plurality of inclined circular walls connectedby blades, an electric motor to revolve said fan and create a blast ofair which is delivered diagonally outward across said resistance mediumsand is also made to travel about in said case to thereby impinge the airagainst a large portion of the exterior of said resistance mediums fromdifferent directions, substantially as described.

3. In an electric heater, an external case open at its outer or deliveryend and adapted to receive air opposite or at its air-receiving end, anelectric motor located in said case and carrying a fan which rotates insaid case between its air-receiving end and its air-delivering end, aresistance medium contained Within said case between its air-receivingand air-delivering ends, said resistance and said motor each derivingtheir electrical energy through independent wires, the construction andarrangement of parts being such as to establish air-currents which aredefined bya combined outward and circular movement of the air within thecase, said current impinging against a substantially large area of theheated resistance medium in said case, substantially as described.

4. In an electric heater, a surrounding case open at its outer ordeliver end, and adapted to receive air at or near its opposite orairreceiving end, an electric motor located in said case and carrying afan which rotates in said case between its air-receiving end and itsdelivering end, and a resistance-coil composed of a ring woundexternally with wire, and means to support said ring inside of butremoved from contact with the interior of said surrounding case betweenits air-receiving and air-delivering end, the blast of air. created bysaid fan having access to the entire exterior surface of saidresistance-coil, substantially as described.

5. In an electric heater, a surrounding case open at its outer ordelivery end and adapted to receive air at or near its opposite orair-receivin g end, an electric motor located therein and carrying a fanwhich rotates in said case between its air-receiving end and itsair-delivering end, and a resistance-coil composed of a ring ofinsulating material occupying an angular position within saidsurrounding case and covered with a fine wire, the blast of air createdby said fan impinging directly against said wire, substantially asdescribed.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

GARDNER G. HAWKINS.

Witnesses:

Gno. W. GREGORY, MARGARET N. DUNN.

